1. Field of the Invention
The present invention relates to a manufacturing method for a semiconductor device and a manufacturing apparatus for a semiconductor device. A film is formed, for example, by supplying process gas onto a wafer while heating the wafer.
2. Description of the Related Art
In recent years, with requirements of low cost and high performance of a semiconductor device, high productivity in a film formation process as well as high quality such as high film thickness uniformity is required.
In an epitaxial film forming apparatus, as a wafer diameter increases, for example, to 200 mm or 300 mm, a single-wafer-processing type has superseded a batch type that processes a plurality of wafers to satisfy the above requirements. Moreover, epitaxial growth conditions have been changed for maintenanceability and requirement of low cost and the like. For example, low-pressure growth using mono-silane has been replaced with atmospheric-pressure growth using an inexpensive Cl based source gas with few deposits such as trichlorosilane (hereinafter referred to as TCS) or dichlorosilane.
However, some semiconductor elements such as IGBT (insulated gate bipolar transistor) require a thick epitaxial film. In performing such thick-film formation, the single-wafer-processing type causes low productivity. Although the batch type has been used to increase productivity in some case, controlling film thickness uniformity is difficult as found in the single-wafer-processing type.
In addition, if the epitaxial film thickness exceeds 100 μm (e.g. 150 μm), an apparatus that has a low film formation rate drastically lowers productivity regardless of single-wafer-processing type or batch type. Accordingly, to improve productivity while maintaining high quality, there has been used a high-speed rotation type manufacturing apparatus that performs epitaxial growth by heating while performing high-speed rotation, for example, at 900 rpm or more, as disclosed in Japanese Patent Application Laid-Open No. 11-67675.
On the other hand, there occurs a problem that polysilicon generated at film formation deposits on wafer retention members. This is common to any epitaxial film forming apparatus. The deposition of polysilicon has an adverse effect upon the members and further serious effects upon wafer quality by particle, adhesion and the like. Accordingly, deposited polysilicon is required to be removed by etching.
However, frequent etching drastically lowers productivity, and repetition of temperature rise and fall accelerates deterioration of the members. Hence, even with the high-speed rotation type film forming apparatus, productivity is lowered and consumables costs are increased.